[1] Hartikainen complained to the human rights committee of the United Nations from the curriculum of the comprehensive school subject of the "uskontojen historia ja siveysoppi" (history of religions and ethics) in 1978.
Hartikainen was the chairman of Finland's Atheist Association (Suomen Ateistiyhdistys) since its establishment on 16 May 1985.
In the 1980s he delivered the doctrine material of the "elämänkatsomustieto" of the irreligious (the history of religions and ethics of that time) into use.
He supported Finnish physicist Kari Enqvist's view, that emergence means 'coarsening' and the losing of information relating to the description of reality (examples: statistical thermodynamics, classical electrodynamics, thinking of an animal etc.)
Hartikainen was a modern logical empiricist and he recommended not using words "a priori truth" and saying "correct by definition" or "derivable from axioms" instead.